Circuit breaker



April 18, 1950 H. G. BAXTER 2,504,793

CIRCUIT BREAKER Filed April 27, 194:5

wrrNEssEs; 2/ (/3 v ,3 INVENTOR 2% f/pm/dax fer, ff

Patented Apr. 18, 1950 CIRCUIT BREAKER Harold G. Baxter, Baldwin, N. Y.,assignor to Westinghouse Electric Cron-poration,` East Pittsburgh, Pa.,a corporation of Pennsylvania Application April 27, 1943, Serial No.484,682

(Cl. 20G-116.)

15 Claims.

This invention relates to circuit breakers, and more particularly tocircuit breakers of the type which may be operated manually and whichare operated automatically in response to overload currents.

An object of the invention is the provision of a circuit breakerhavingan improved operating mechanism in which the point of operation ofthe operating member is variable from one position to another,-depending on Whether the operetion is manual or automatic.

1 Anotherobject of the invention is the provision of a circuit breakerembodying an improved operating mechanism wherein an operating member isprovided with a plurality of centers of rotation, the member beingmanually or otherwise operable about one of the centers and beingautomatically operable about another of the centers.

Another obj ect`l of the invention is the provision of a circuit breakerembodying an improved operating mechanism wherein an operating member isprovided which has a pair of centers of rotation, one of the centersbeing releasably restrained by a trip device, the operating member beingmanuf ally operable about the restrained center and automaticallyoperable about the other 4center upon release of` the restrained center.

Another object ofthe invention is the provision of a circuit breakerhaving an-improved operating mechanism wherein an operating member isoperable about apair of spaced pivots, one of the pivots beingreleasably restrained to provide for manual operation of the member andbreaker, n

said one pivot being releasable to effect automatic operation of theoperating member and breaker.

Another object of the invention is the provision of a circuit breakerhaving an improved operating mechanism which, when moved to an lintermediate position and then released, will open and automaticallyreclose the contacts.

Another objectof, the invention is the provision of a circuit breakerwith an improved operating mechanism having. an intermediate positionfrom 2 thereof when read in conjunction with the accompanying drawing,in which:

Figure l is a side-elevational view, with the side-cover plate removed,of a circuit breaker embodying the principles of the invention. Thebreaker mechanism is shown in vfull lines in the closed position and indotted lines in the manually opened position.

Fig. 2 is a fragmentary-elevational view of the mechanism shown in Fig.l, but showing the breaker mechanism in the tripped-open position.

Fig. 3 is a side-elevational view of a modicatien of the breakermechanism shown in Fis., 1, the mechanism being shown in full lines inthe closed position and in dotted lines in the manually-opened position.

Fig. 4 is a side-elevational view oi the breaker mechanism shown in Fig.3, but showing the mechanism in the tripped-open position.

Referring to Fig. l of the drawing, the circuitbreaker mechanism ismounted in a casing H of molded-insulating material having a baseportion lf3, a side Wall l5, end `walls Il, and a slotted outer wall I9.A cover plate 2l (shown partly broken away), also of molded-insulatingmaterial, is secured to the open side of the casing` I i by means ofscrews' 23 (only one being shown) which pass through holes in the coverplate 2| and matching holes 25 in the casing Il. Terminals 2l and 29 aresupported in suitable slots in the casing Il and are held in place bythe cover plate 2 I. The terminal 21 extends into the interior of thecasing Il and has secured to its inner end a stationary contact 3l withwhich a movable contact 33 cooperates. The movable contactv 33 issecured to thefree end of a pivoted L-shaped switch memberor contact arm35. The pivoted end of the contact arm 35 is bifurcated and the two legsare pivotally supported on pins 31 one projecting inwardly from the sidewall l5 and the other (not shown) projecting inwardly from the coverplate 2l. An over-center spring 39 has one end anchored to a pin 4Isupported in the legs of the switch. member or contact arm 35. The otherend of the spring 39 is hooked over a pin 43 mounted on an operatinghandle 45 movable between an on position and an oit position. The innerend of the operating handle 45 is U-shaped and the two legs carry pins4T and-49 extending on both sides of their respective legs. The pins 41and i9 project respectively into arcuate slots Sl and 53 molded in theside wall l5 and into matching slots (not shown) molded in the coverplate 2|.

The overcenter spring 35 biases the switch the switch` member.

wse'fr'om its full-line position (Fig. 3) to its `diitix-zd-lineposition. Due to the pin and slot 'connection 'M -69 movement of thehandle 65 is transmitted to the operating member 13l which, uponcounterclockwise'movement of the handle, rotates in the same directionabout the pin 49 as a pivot. During 'the counterclockwise rotation ofthe operating member 153, the spring 39 is moved overcenter to the leftof the pivot pin 31 for the switch members'35'and this arm is then movedto open the contacts with a snap action. Continued movement of thehandle 65 in opening direction carries the spring 39 to the left of thepivot pin 49 in which position the spring biases the switch member-35',the operating member 13 and, due to the lpin and slotconnection 'ifi-69,

'the handle `6 5 to their oit-positions.

The contacts are operatedtothe closed position by manual movementvofthe' handle 65 in a clockwise direction to its on or full lineposition (Fig. 3). Early in this movement, the spring 39 passes to therightl of the pivot pin 49 where it biases the operating member 'i3 inclosing direction. Later in the clockwise movement of the handle thesprin'g`39 crosses tothe right of the pivot pin 31 andvv closes thecontacts with a snap action.

In both embodiments ofthe invention, if the handle'ti is not moved 'toits off position during an opening operation by the handle, that is, ii'

the handle is'moved'to the intermediate position wherein kthe centerlineof the spring 39 lies between'the pivot `pins "31 and 49, the contactswill have opened, but: if the handle is released without moving it tothe full-open position, the spring 39 will immediately' move theoperating member and the handle to the on position. This willautomatically'reclose the contacts as the spring moves to the right ofthe pivot 31 for However, if the handle is movedv to its ofi position,it will, as previously stated, move the spring 39 to theleft of thepivot .pin 49 where the spring will bias lthe handle 45 (Fig.` 1`) 'orthe operating member I3 (Fig. 3)

`in their respective off positions and' maintain the switch member inthe open position untilthe handle is` manually displaced" in closingdirection.

An advantage of' the invention is that the breaker may be controlledfrom a remote point to open the contacts, and upon deenergization of thecontrol means, the-contacts will be immediately reclosed by theoperating spring. In order rto accomplish this 'function it is necessaryto actuate the operating mechanism in opening Ydirection only to theintermediate position. Any

suitable remotely-controllablev actuating means Amay be employed'.

Having described several embodiments of the invention in accordance withthe patent statues, it is to be understood that various changes andmodifications may bemade therein without departing from someof theessential features of the invention;

Iclaim as my invention:

1. Acircuitbreaker compri'singa'switch mem- `'responsive' means:operableto permit said operating-.membertorbezmovedtabouttanother of.said 75 pivots to thereby effect Aan. automatic opening movement ofsaid 'switclrmemben 2. A circuit breaker comprising a switch membermounted on a fixed pivot and movable to an open and to a closedposition,an operating member having a plurality of spaced pivots, said operatingmember being operable about either of said pivots to effect openingmovement of said switch member with a snap action, manuallyoperablemeans for moving said operating member about one of said pivots, andcurrent responsive means operable when heated a` predetermined amount topermit said operating member to be moved about another of said pivots,said manually-operable means being operable to move said operatingmember about either pivot to move the switch member to closed positionwith a snap action.

3. A circuit breaker comprising a switch member movable-to open andclosed positions, operating means for said switch member comprising amember having a plurality of pivots, an overcenter spring operable bysaid member to cause movement of said switch member to open and closedpositions, a bimetal element normally supporting one of said pivots toreleasably restrain said operating member, said bimetal element beingoperable when heated apredetermined amount to releasesaid one pivot andpermit operation of the operating member about another of said pivots toeffect movement oi the switch member to open position, and manuallyoperable means for operating said operating member about vsaid one pivotto eiect opening movement of the switch member.

fi. A circuit breaker comprising a switch'mer-.ioperating mechanism forsaid switch meinber comprising an operating member movable to an oiposition and to an on position, an overcenter spring operativelyconnecting the switch member and said operating member operable to causemovementof said switch member to an open position and toa closedposition with a snap action, a plurality oi spaced pivots for saidoperating member, means for reieasably restraining one of said pivots,said restraining means `being responsive to predetermined abnormalcircuit conditions to release said one pivot and permit the overcenterspring to opcratethe operating member about another of said pivots toeffect opening movement of the switch member, and means foroperatingsaid operating member about said one pivot to effect openingmovement of the switchniember.

5. A circuit breaker comprising a switch niember, operating mechanismfor said switch member comprising a member operable about a plurality ofpivots to off and on positions, an overcenter spring operativelyconnecting the switch member and 'the operating member to cause movementof the switch member to cpen and ciosed positions with a snap action,electroresponsive means engaging and supporting one ofpivotsto-releasably restrain said opereting member in the on position,said electroresponsive means beingoperabie in' response toVpredetermined circuit' conditions to releasesaid operating member topermit said overc'enter spring to operate said operating member aboutanother of said pivots to effect automatic opening oi. switch member,and manual means for operating said operating member about said onepivot to operate saidswitch'meniber.

6. A circuit breaker comprising a switch memf ber,operatingmechamsmfor.said switchimember aso-139e comprising an operatingmember movable to effeet opening and closing movement of said switchmember, an overcenter spring operable by said voperating member to movesaid switch member to open and closed positions with a snap action, aplurality of pivots on said operating member one of said pivots beingreleasable to effect automatic movement of said operating member inopening direction, a trip device for releasably restraining saidreleasable pivot, said trip device being responsive to overload currentsto release said releasable pivot and permit said overcenter spring tomove the operating member about a second of said pivots, and manuallyoperable means operatively connected to said operating member foroperating said member about the releasable pivot to effect manualopening of said switch member.

7. A circuit breaker comprising relatively movable contacts, releasableoperating mechanism .for causing automatic opening of said contacts,

said operating mechanism including an operat- Aing member having a pairof spaced pivots, means 8. A circuit breaker comprising relativelymovable contacts, operating mechanism for causing automatic opening ofsaid contacts, said operating mechanism including a releasable memberhaving a pair of spaced pivots, an overcenter spring operable by saidreleasable member tocause opening and closing of the contacts with asnap action, means for rotating the releasable member about one of saidpivots to open and close the contacts, and a trip device operable inresponse to predetermined abnormal circuit conditions to release saidreleasable member and permit said member to rotate about the other pivotto automatically open the contacts.

9. A circuit breaker comprising relatively movable contacts, operatingmechanism for said contacts, a releasable member having a pair of spacedpivots and operable to cause automatic opening of the contacts, meanscomprising an overcenter spring operable by said releasable member tocause opening and closing of said contacts with a snap action, manuallyoperable means operatively associated with said releasable member foroperating said member about one of said pivots to open and close saidcontacts, and current-responsive means operable when heated apredetermined amount to release the releasable member and thereby permitoperation of said member about the other` pivot to automatically openthe contacts.

10. A circuit breaker comprising relatively movable contacts, operatingmechanism for said lcontacts including a releasable operating handleprovided with a plurality of pivots, said operating handle beingmanually operable about one of said pivots to off and on positions,means operable by said handle when said handle is moved to ofi and onpositions to cause opening and closing of said contacts, andelectroregsponsive means normally engaging said one pivot to restrainsaid handle in said "on position, said electroresponsive means beingoperable to release said handle and thereby permit movement of saidhandle about another of said pivots to effect automatic opening of saidcontacts.

11. A circuit breaker comprising relatively movable contacts, operatingmechanism for said contacts including a releasable member provided witha plurality of pivots, an operating handle operatively related to saidreleasable member, said handle being operable to move the releasablemember about one of said pivots to open and close said contacts with asnap action, means operable by said releasable member to effect openingand closing of said contacts, and a trip device operable to permitmovement of said releasable member about another of said pivots toeffect automatic opening of the contacts.

12. A circuit breaker comprising relatively movable contacts, operatingmechanism for said contacts including a releasable member provided witha plurality of pivots, means operable by said releasable mem-ber to openand close said contacts, manually-operable means having a pin and slotconnection with said releasable member, said manual means being operableto move the releasable member about one of said pivots to open and closethe contacts, a bimetal element for releasably restraining said onepivot, said bimetal element being operable when heated in response tooverload currents to release said one pivot and thereby permit thereleasable member to move about another of the pivots to effectautomatic opening of the contacts, said manual means being operable tomove the releasable member about the other pivot to effect closing ofthe contacts.

13. A circuit breaker comprising relatively rmovable contacts, operatingmechanism including an operating member movable to an intermediateposition and to an olf position to elect .opening of said Contacts, atrip device operable in response to abnormal circuit conditions toeffect automatic opening of said contacts, and means for operating saidoperating member from said intermediate position to automatically closethe contacts, said operating membel` when moved 'to said off positionmaintaining said contacts in the open position.

14. A circuit .breaker comprising relatively movable contacts, operatingmechanism for said contacts, said operating member being automaticallyoperable about said one pivot from said operating member in said oifposition maintaining said contacts in the open position, and

a trip device operable in response to abnormal circuit conditions toeffect movement of said operating member about the other of said pivotsto vcause automatic opening of said contacts.

l5. A circuit breaker comprising relatively .movable contacts, operatingmeans for said con- 75 a trip device operable' in response to abnormalcircuit conditions to permit said over-center spring to operate saidoperating member about a le of this patent: 10

UNITED STATES PATENTS Number Name Date second pivot to cause automaticopening of said 2,073,103 Hodgkins Man 9, 1937 0ntCtS 2,107,246 JacksonFeb. 1, 193s 5 2 188 949 Jackson Feb 6 1940 H LD G. BAXTER.

ARO 2,212,732 Fisher Apr. 27, 1940 REFERENCES CITED 2,315,633 May Apr.6, 1943 T f l i d i th, 2,320,357 Platz et al. June 1, 1943 he G1 Owingfe @ences are 0 lecor n e 2,371,733 christofferson Mar. 20, 1945

